Optimization of intensive rearing strategies for largemouth bass (Micropterus nigricans) during the early stages

Abstract

The transition from endogenous to exogenous feeding of largemouth bass (Micropterus nigricans) limits production under intensive recirculating aquaculture systems (RAS). This thesis had two main objectives aimed at improving larviculture in indoor RAS. Objective 1 determined the optimal larval stocking density (LD; 25, 50, 100 larvae/L) and prey density (PD; 2, 4, 8 Artemia/mL) combination. Objective 2 evaluated larval performance at 100 larvae/L under static (PD12, PD16, PD20) and progressive PD regimens (PD8-12, PD8-12-16, PD8-12-16-20), relative to a control (LD25×PD8). Morphometrics, survival, cannibalism, biomass, individual weights, condition index, and specific growth rate (SGR) were measured throughout early ontogeny. In Objective 1, larvae were largest at LD25×PD8 (23 to 128 mm²) and smallest at LD100×PD2 (13 to 64 mm²). Survival (90%) and cannibalism (<1%) were most favorable at LD25×PD8, whereas biomass peaked at LD100×PD8 (200 g/tank). In Objective 2, the largest fish were observed in the control and PD20 treatments, followed by the PD8-12 regimen. Survival was highest in control (87%) and lowest in PD20 (51%). Highest biomass was achieved in PD20 (572 g) followed by PD16 (560 g) and PD8-12-16-20 (546 g). Cannibalism was <10% in control but increased to 40% in the PD20 treatment. Overall, progressive PD regimens supported growth comparable to the control while facilitating intensive larviculture.